I can't agree with you more on this subject. Partly it is the new found money and status for people who are not yet ready to take it. Everyone, well almost everyone, wants to show how busy or important they are, without having the slightest of respect for the fellow passenger.
Whenever I travel back to India, not a single staff in the immigration or any other staff in the airport has greeted me with a smile. Is it so expensive to wear a smile? I won't consider my country to be progressed until all the people in our country learn to live like humans.